Backlight unit and liquid crystal display device including the same

Abstract

A backlight unit for a liquid crystal display device including a liquid crystal panel, includes: a light source including a light-emitting diode (“ED”) which generates and emits light; and a light converting layer between the light source and the liquid crystal panel, spaced apart from the light source, and converting the light from the light source into white light and emitting the white light toward the liquid crystal panel. The light converting layer includes: semiconductor nanocrystals, and a barrier material which restricts penetration of moisture or oxygen.

What is claimed is: 
     
       1. A backlight unit for a liquid crystal display device comprising a liquid crystal panel, the backlight unit comprising:
 a light source comprising a light-emitting diode which generates and emits light; and 
 a light converting layer between the light source and the liquid crystal panel, and spaced apart from the light source, wherein the light converting layer converts the light from the light source into another light and emits the another light toward the liquid crystal panel, 
 the light converting layer comprising:
 semiconductor nanocrystals, and 
 a barrier material disposed in the light converting layer to have a moisture transmission rate and an oxygen transmission rate of equal to or less than about 0.1 cc/m 2 /day. 
 
 
     
     
       2. The backlight unit of  claim 1 , wherein the light converting layer further comprises:
 a transparent substrate, 
 a light converting film on a surface of the transparent substrate, and comprising the semiconductor nanocrystals, and 
 a barrier layer on a surface of the light converting film, and comprising the barrier material. 
 
     
     
       3. The backlight unit of  claim 2 , wherein the barrier layer is further on a surface of the transparent substrate, opposite to the surface of the light converting film. 
     
     
       4. The backlight unit of  claim 1 , wherein the light converting layer further comprises:
 a light converting film comprising the semiconductor nanocrystals, and 
 a barrier layer on a surface of the light converting film, and comprising the barrier material. 
 
     
     
       5. The backlight unit of  claim 1 , wherein the light converting layer further comprises a light converting film comprising the semiconductor nanocrystals and the barrier material. 
     
     
       6. The backlight unit of  claim 5 , wherein the light converting layer further comprises a barrier layer on a surface of the light converting film, and comprising the barrier material. 
     
     
       7. The backlight unit of  claim 6 , wherein the barrier material of the light converting film restricts penetration of one of the moisture and the oxygen, and the barrier material of the barrier layer restricts penetration of the other of the moisture and the oxygen. 
     
     
       8. The backlight unit of  claim 1 , further comprising a plurality of light converting layers which converts the light into light of different colors. 
     
     
       9. The backlight unit of  claim 8 , wherein the plurality of light converting layers are arranged to have an emission wavelength with lower energy as a distance from the light source decreases. 
     
     
       10. The backlight unit of  claim 8 , wherein the plurality of light converting layers is spaced apart from one another, and a blank layer is defined between adjacent light converting layers of the plurality of light converting layers. 
     
     
       11. The backlight unit of  claim 1 , wherein the barrier material comprises at least one selected from an organic material and an inorganic material. 
     
     
       12. The backlight unit of  claim 11 , wherein the barrier material comprises the organic material and the inorganic material repeatedly alternated in a stack. 
     
     
       13. The backlight unit of  claim 11 , wherein
 the organic material comprises at least one selected from thiolene, hybrid epoxy, polyurea, polytetrafluoroethylene, polydimethylsiloxane, polyvinylchloride, polycarbonate, polystyrene, polyimide, parylene, polyethylacrylate, and polymethylmethacrylate, and 
 the inorganic material comprises at least one selected from silicon oxide, aluminum oxide, titanium oxide, indium oxide, tin oxide, indium oxide, tantalum oxide, zirconium oxide, and niobium oxide. 
 
     
     
       14. The backlight unit of  claim 1 , further comprising a diffusive plate between the light source and the light converting layer, or between the light converting layer and the liquid crystal panel. 
     
     
       15. The backlight unit of  claim 14 , wherein the light converting layer contacts a surface of the diffusive plate. 
     
     
       16. The backlight unit of  claim 1 , wherein the light converting layer further comprises light diffusing particles which diffuse the light. 
     
     
       17. The backlight unit of  claim 16 , wherein the light converting layer further comprises:
 a light-converting diffusive film comprising the semiconductor nanocrystals and the light diffusing particles, and 
 a barrier layer on a surface of the light-converting diffusive film, and comprising the barrier material. 
 
     
     
       18. The backlight unit of  claim 16 , wherein the light converting layer further comprises a light-converting diffusive film comprising the semiconductor nanocrystals, the barrier material and the light diffusing particles. 
     
     
       19. The backlight unit of  claim 18 , wherein the light converting layer further comprises a barrier layer on a surface of the light-converting diffusive film, and comprising the barrier material. 
     
     
       20. The backlight unit of  claim 1 , further comprising an adhesive layer on a side surface of the light converting layer, and comprising the barrier material. 
     
     
       21. The backlight unit of  claim 1 , further comprising a light guide plate between the light source and the light converting layer, wherein the light guide plate guides the light toward the light converting layer. 
     
     
       22. The backlight unit of  claim 21 , wherein
 the light guide plate comprises a light emitting first surface, a second surface opposite to the light emitting first surface, and a side surface connecting the first and second surfaces to each other, and 
 the light source faces the side surface of the light guide plate. 
 
     
     
       23. The backlight unit of  claim 1 , further comprising an optical sheet between the light source and the liquid crystal panel, and comprising at least one selected from a prism sheet, a brightness enhancement sheet and a micro-lens sheet. 
     
     
       24. The backlight unit of  claim 1 , wherein the light source emits blue light or ultraviolet light. 
     
     
       25. The backlight unit of  claim 1 , wherein the light source comprises:
 a substrate, and 
 a plurality of light-emitting diodes on the substrate. 
 
     
     
       26. A liquid crystal display device comprising:
 a light source comprising a light-emitting diode which generates and emits light; 
 a light converting layer spaced apart from the light source, wherein the light converting layer converts the light from the light source into another light and outputs the another light toward a liquid crystal panel, 
 the light converting layer comprising:
 semiconductor nanocrystals, and 
 a barrier material disposed in the light converting layer to have a moisture transmission rate and an oxygen transmission rate of equal to or less than about 0.1 cc/m 2 /day; and 
 
 the liquid crystal panel which forms an image using the another light from the light converting layer. 
 
     
     
       27. The liquid crystal display device of  claim 26 , wherein the light converting layer further comprises:
 a transparent substrate, 
 a light converting film on a surface of the transparent substrate, and comprising the semiconductor nanocrystals, and 
 a barrier layer on a surface of the light converting film, and comprising the barrier material. 
 
     
     
       28. The liquid crystal display device of  claim 27 , wherein the barrier layer is further on a surface of the transparent substrate, opposite to the surface of the light converting film. 
     
     
       29. The liquid crystal display device of  claim 26 , wherein the light converting layer further comprises:
 a light converting film comprising the semiconductor nanocrystals, and 
 a barrier layer on a surface of the light converting film, and comprising the barrier material. 
 
     
     
       30. The liquid crystal display device of  claim 26 , wherein the light converting layer further comprises a light converting film comprising the semiconductor nanocrystals and the barrier material. 
     
     
       31. The liquid crystal display device of  claim 30 , wherein the light converting layer further comprises a barrier layer on a surface of the light converting film, and comprising the barrier material. 
     
     
       32. The liquid crystal display device of  claim 26 , wherein the barrier material comprises at least one selected from an organic material and an inorganic material. 
     
     
       33. The liquid crystal display device of  claim 26 , further comprising a diffusive plate between the light source and the light converting layer, or between the light converting layer and the liquid crystal panel. 
     
     
       34. The liquid crystal display device of  claim 26 , wherein the light converting layer further comprises light diffusing particles which diffuse the light. 
     
     
       35. The liquid crystal display device of  claim 34 , wherein the light converting layer further comprises:
 a light-converting diffusive film comprising the semiconductor nanocrystals and the light diffusing particles, and 
 a barrier layer on a surface of the light-converting diffusive film, and comprising the barrier material. 
 
     
     
       36. The liquid crystal display device of  claim 34 , wherein the light converting layer further comprises a light-converting diffusive film comprising the semiconductor nanocrystals, the barrier materials and the light diffusing particles. 
     
     
       37. The liquid crystal display device of  claim 26 , further comprising a light guide plate between the light source and the light converting layer, wherein the light guide plate guides the light emitted from the light source toward the light converting layer. 
     
     
       38. The liquid crystal display device of  claim 37 , wherein
 the light guide plate comprises a light emitting first surface, a second surface opposite to the light emitting first surface, and a side surface connecting the first and second surfaces to each other, and 
 the light source faces the side surface of the light guide plate.